<u>Answer:</u> The molarity of citric acid that is commercially available lemon juice is 0.416 M
<u>Explanation:</u>
To calculate the concentration of acid, we use the equation given by neutralization reaction:

where,
are the n-factor, molarity and volume of acid which is 
are the n-factor, molarity and volume of base which is NaOH.
We are given:

Putting values in above equation, we get:

Hence, the molarity of citric acid that is commercially available lemon juice is 0.416 M
A is correct because there is no reaction involved
Answer:
4HCl(g) + O₂(g) → 2Cl₂(g) + 2H₂O(g)
Explanation:
In order to find the equation we should state:
The reactants → Hydrogen chloride (HCl) and oxygen (O₂)
The products → Chlorine gas (Cl₂) and water gas (H₂O)
The balanced equation is:
4HCl + O₂ → 2Cl₂ + 2H₂O
It is a redox reaction, where the oxygen reduces to make water, and the chloride is oxidized to produce elemental chlorine.